/*
* Copyright 2008 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using ByteMatrix = ThinkAway.Drawing.Barcode.Common.ByteMatrix;
using ErrorCorrectionLevel = ThinkAway.Drawing.Barcode.qrcode.decoder.ErrorCorrectionLevel;
namespace ThinkAway.Drawing.Barcode.qrcode.encoder
{
	
	/// <author>  satorux@google.com (Satoru Takabayashi) - creator
	/// </author>
	/// <author>  dswitkin@google.com (Daniel Switkin) - ported from C++
	/// </author>
	/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source 
	/// </author>
	public static class MatrixUtil
	{
	    //UPGRADE_NOTE: Final was removed from the declaration of 'POSITION_DETECTION_PATTERN'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
		private static readonly int[][] POSITION_DETECTION_PATTERN = new int[][]{new int[]{1, 1, 1, 1, 1, 1, 1}, new int[]{1, 0, 0, 0, 0, 0, 1}, new int[]{1, 0, 1, 1, 1, 0, 1}, new int[]{1, 0, 1, 1, 1, 0, 1}, new int[]{1, 0, 1, 1, 1, 0, 1}, new int[]{1, 0, 0, 0, 0, 0, 1}, new int[]{1, 1, 1, 1, 1, 1, 1}};
		
		//UPGRADE_NOTE: Final was removed from the declaration of 'HORIZONTAL_SEPARATION_PATTERN'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
		private static readonly int[][] HORIZONTAL_SEPARATION_PATTERN = new int[][]{new int[]{0, 0, 0, 0, 0, 0, 0, 0}};
		
		//UPGRADE_NOTE: Final was removed from the declaration of 'VERTICAL_SEPARATION_PATTERN'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
		private static readonly int[][] VERTICAL_SEPARATION_PATTERN = new int[][]{new int[]{0}, new int[]{0}, new int[]{0}, new int[]{0}, new int[]{0}, new int[]{0}, new int[]{0}};
		
		//UPGRADE_NOTE: Final was removed from the declaration of 'POSITION_ADJUSTMENT_PATTERN'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
		private static readonly int[][] POSITION_ADJUSTMENT_PATTERN = new int[][]{new int[]{1, 1, 1, 1, 1}, new int[]{1, 0, 0, 0, 1}, new int[]{1, 0, 1, 0, 1}, new int[]{1, 0, 0, 0, 1}, new int[]{1, 1, 1, 1, 1}};
		
		// From Appendix E. Table 1, JIS0510X:2004 (p 71). The table was double-checked by komatsu.
		//UPGRADE_NOTE: Final was removed from the declaration of 'POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
		private static readonly int[][] POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE = new int[][]{new int[]{- 1, - 1, - 1, - 1, - 1, - 1, - 1}, new int[]{6, 18, - 1, - 1, - 1, - 1, - 1}, new int[]{6, 22, - 1, - 1, - 1, - 1, - 1}, new int[]{6, 26, - 1, - 1, - 1, - 1, - 1}, new int[]{6, 30, - 1, - 1, - 1, - 1, - 1}, new int[]{6, 34, - 1, - 1, - 1, - 1, - 1}, new int[]{6, 22, 38, - 1, - 1, - 1, - 1}, new int[]{6, 24, 42, - 1, - 1, - 1, - 1}, new int[]{6, 26, 46, - 1, - 1, - 1, - 1}, new int[]{6, 28, 50, - 1, - 1, - 1, - 1}, new int[]{6, 30, 54, - 1, - 1, - 1, - 1}, new int[]{6, 32, 58, - 1, - 1, - 1, - 1}, new int[]{6, 34, 62, - 1, - 1, - 1, - 1}, new int[]{6, 26, 46, 66, - 1, - 1, - 1}, new int[]{6, 26, 48, 70, - 1, - 1, - 1}, new int[]{6, 26, 50, 74, - 1, - 1, - 1}, new int[]{6, 30, 54, 78, - 1, - 1, - 1}, new int[]{6, 30, 56, 82, - 1, - 1, - 1}, new int[]{6, 30, 58, 86, - 1, - 1, - 1}, new int[]{6, 34, 62, 90, - 1, - 1, - 1}, new int[]{6, 28, 50, 72, 94, - 1, - 1}, new int[]{6, 26, 50, 74, 98, - 1, - 1}, new int[]{6, 30, 54, 78, 102, - 1, - 1}, new int[]{6, 28, 54, 80, 106, - 1, - 1}, new int[]{6, 32, 58, 84, 110, - 1, - 1}, new int[]{6, 30, 58, 86, 114, - 1, - 1}, new int[]{6, 34, 62, 90, 118, - 1, - 1}, new int[]{6, 26, 50, 74, 98, 122, - 1}, new int[]{6, 30, 54, 78, 102, 126, - 1}, new int[]{6, 26, 52, 78, 104, 130, - 1}, new int[]{6, 30, 56, 82, 108, 134, - 1}, new int[]{6, 34, 60, 86, 112, 138, - 1}, new int[]{6, 30, 58, 86, 114, 142, - 1}, new int[]{6, 34, 62, 90, 118, 146, - 1}, new int[]{6, 30, 54, 78, 102, 126, 150}, new int[]{6, 24, 50, 76, 102, 128, 154}, new int[]{6, 28, 54, 80, 106, 132, 158}, new int[]{6, 32, 58, 84, 110, 136, 162}, new int[]{6, 26, 54, 82, 110, 138, 166}, new int[]{6, 30, 58, 86, 114, 142, 170}};
		
		// Type info cells at the left top corner.
		//UPGRADE_NOTE: Final was removed from the declaration of 'TYPE_INFO_COORDINATES'. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
		private static readonly int[][] TYPE_INFO_COORDINATES = new int[][]{new int[]{8, 0}, new int[]{8, 1}, new int[]{8, 2}, new int[]{8, 3}, new int[]{8, 4}, new int[]{8, 5}, new int[]{8, 7}, new int[]{8, 8}, new int[]{7, 8}, new int[]{5, 8}, new int[]{4, 8}, new int[]{3, 8}, new int[]{2, 8}, new int[]{1, 8}, new int[]{0, 8}};
		
		// From Appendix D in JISX0510:2004 (p. 67)
		private const int VERSION_INFO_POLY = 0x1f25; // 1 1111 0010 0101
		
		// From Appendix C in JISX0510:2004 (p.65).
		private const int TYPE_INFO_POLY = 0x537;
		private const int TYPE_INFO_MASK_PATTERN = 0x5412;
		
		// Set all cells to -1.  -1 means that the cell is empty (not set yet).
		//
		// JAVAPORT: We shouldn't need to do this at all. The code should be rewritten to begin encoding
		// with the ByteMatrix initialized all to zero.
		public static void  clearMatrix(ByteMatrix matrix)
		{
			matrix.Clear((sbyte) (- 1));
		}
		
		// Build 2D matrix of QR Code from "dataBits" with "ecLevel", "version" and "getMaskPattern". On
		// success, store the result in "matrix" and return true.
		public static void  buildMatrix(BitVector dataBits, ErrorCorrectionLevel ecLevel, int version, int maskPattern, ByteMatrix matrix)
		{
			clearMatrix(matrix);
			embedBasicPatterns(version, matrix);
			// Type information appear with any version.
			embedTypeInfo(ecLevel, maskPattern, matrix);
			// Version info appear if version >= 7.
			maybeEmbedVersionInfo(version, matrix);
			// Data should be embedded at end.
			EmbedDataBits(dataBits, maskPattern, matrix);
		}
		
		// Embed basic patterns. On success, modify the matrix and return true.
		// The basic patterns are:
		// - Position detection patterns
		// - Timing patterns
		// - Dark dot at the left bottom corner
		// - Position adjustment patterns, if need be
		public static void  embedBasicPatterns(int version, ByteMatrix matrix)
		{
			// Let's get started with embedding big squares at corners.
			EmbedPositionDetectionPatternsAndSeparators(matrix);
			// Then, embed the dark dot at the left bottom corner.
			EmbedDarkDotAtLeftBottomCorner(matrix);
			
			// Position adjustment patterns appear if version >= 2.
			MaybeEmbedPositionAdjustmentPatterns(version, matrix);
			// Timing patterns should be embedded after position adj. patterns.
			EmbedTimingPatterns(matrix);
		}
		
		// Embed type information. On success, modify the matrix.
		public static void  embedTypeInfo(ErrorCorrectionLevel ecLevel, int maskPattern, ByteMatrix matrix)
		{
			BitVector typeInfoBits = new BitVector();
			MakeTypeInfoBits(ecLevel, maskPattern, typeInfoBits);
			
			for (int i = 0; i < typeInfoBits.size(); ++i)
			{
				// Place bits in LSB to MSB order.  LSB (least significant bit) is the last value in
				// "typeInfoBits".
				int bit = typeInfoBits.at(typeInfoBits.size() - 1 - i);
				
				// Type info bits at the left top corner. See 8.9 of JISX0510:2004 (p.46).
				int x1 = TYPE_INFO_COORDINATES[i][0];
				int y1 = TYPE_INFO_COORDINATES[i][1];
				matrix.SetRenamed(x1, y1, bit);
				
				if (i < 8)
				{
					// Right top corner.
					int x2 = matrix.Width - i - 1;
					int y2 = 8;
					matrix.SetRenamed(x2, y2, bit);
				}
				else
				{
					// Left bottom corner.
					int x2 = 8;
					int y2 = matrix.Height - 7 + (i - 8);
					matrix.SetRenamed(x2, y2, bit);
				}
			}
		}
		
		// Embed version information if need be. On success, modify the matrix and return true.
		// See 8.10 of JISX0510:2004 (p.47) for how to embed version information.
		public static void  maybeEmbedVersionInfo(int version, ByteMatrix matrix)
		{
			if (version < 7)
			{
				// Version info is necessary if version >= 7.
				return ; // Don't need version info.
			}
			BitVector versionInfoBits = new BitVector();
			MakeVersionInfoBits(version, versionInfoBits);
			
			int bitIndex = 6 * 3 - 1; // It will decrease from 17 to 0.
			for (int i = 0; i < 6; ++i)
			{
				for (int j = 0; j < 3; ++j)
				{
					// Place bits in LSB (least significant bit) to MSB order.
					int bit = versionInfoBits.at(bitIndex);
					bitIndex--;
					// Left bottom corner.
					matrix.SetRenamed(i, matrix.Height - 11 + j, bit);
					// Right bottom corner.
					matrix.SetRenamed(matrix.Height - 11 + j, i, bit);
				}
			}
		}
		
		// Embed "dataBits" using "getMaskPattern". On success, modify the matrix and return true.
		// For debugging purposes, it skips masking process if "getMaskPattern" is -1.
		// See 8.7 of JISX0510:2004 (p.38) for how to embed data bits.
		public static void  EmbedDataBits(BitVector dataBits, int maskPattern, ByteMatrix matrix)
		{
			int bitIndex = 0;
			int direction = - 1;
			// Start from the right bottom cell.
			int x = matrix.Width - 1;
			int y = matrix.Height - 1;
			while (x > 0)
			{
				// Skip the vertical timing pattern.
				if (x == 6)
				{
					x -= 1;
				}
				while (y >= 0 && y < matrix.Height)
				{
					for (int i = 0; i < 2; ++i)
					{
						int xx = x - i;
						// Skip the cell if it's not empty.
						if (!IsEmpty(matrix.GetRenamed(xx, y)))
						{
							continue;
						}
						int bit;
						if (bitIndex < dataBits.size())
						{
							bit = dataBits.at(bitIndex);
							++bitIndex;
						}
						else
						{
							// Padding bit. If there is no bit left, we'll fill the left cells with 0, as described
							// in 8.4.9 of JISX0510:2004 (p. 24).
							bit = 0;
						}
						
						// Skip masking if mask_pattern is -1.
						if (maskPattern != - 1)
						{
							if (MaskUtil.getDataMaskBit(maskPattern, xx, y))
							{
								bit ^= 0x1;
							}
						}
						matrix.SetRenamed(xx, y, bit);
					}
					y += direction;
				}
				direction = - direction; // Reverse the direction.
				y += direction;
				x -= 2; // Move to the left.
			}
			// All bits should be consumed.
			if (bitIndex != dataBits.size())
			{
				throw new WriterException("Not all bits consumed: " + bitIndex + '/' + dataBits.size());
			}
		}
		
		// Return the position of the most significant bit set (to one) in the "value". The most
		// significant bit is position 32. If there is no bit set, return 0. Examples:
		// - findMSBSet(0) => 0
		// - findMSBSet(1) => 1
		// - findMSBSet(255) => 8
		public static int FindMsbSet(int value_Renamed)
		{
			int numDigits = 0;
			while (value_Renamed != 0)
			{
				value_Renamed = SupportClass.URShift(value_Renamed, 1);
				++numDigits;
			}
			return numDigits;
		}
		
		// Calculate BCH (Bose-Chaudhuri-Hocquenghem) code for "value" using polynomial "poly". The BCH
		// code is used for encoding type information and version information.
		// Example: Calculation of version information of 7.
		// f(x) is created from 7.
		//   - 7 = 000111 in 6 bits
		//   - f(x) = x^2 + x^2 + x^1
		// g(x) is given by the standard (p. 67)
		//   - g(x) = x^12 + x^11 + x^10 + x^9 + x^8 + x^5 + x^2 + 1
		// Multiply f(x) by x^(18 - 6)
		//   - f'(x) = f(x) * x^(18 - 6)
		//   - f'(x) = x^14 + x^13 + x^12
		// Calculate the remainder of f'(x) / g(x)
		//         x^2
		//         __________________________________________________
		//   g(x) )x^14 + x^13 + x^12
		//         x^14 + x^13 + x^12 + x^11 + x^10 + x^7 + x^4 + x^2
		//         --------------------------------------------------
		//                              x^11 + x^10 + x^7 + x^4 + x^2
		//
		// The remainder is x^11 + x^10 + x^7 + x^4 + x^2
		// Encode it in binary: 110010010100
		// The return value is 0xc94 (1100 1001 0100)
		//
		// Since all coefficients in the polynomials are 1 or 0, we can do the calculation by bit
		// operations. We don't care if cofficients are positive or negative.
		public static int CalculateBchCode(int value_Renamed, int poly)
		{
			// If poly is "1 1111 0010 0101" (version info poly), msbSetInPoly is 13. We'll subtract 1
			// from 13 to make it 12.
			int msbSetInPoly = FindMsbSet(poly);
			value_Renamed <<= msbSetInPoly - 1;
			// Do the division business using exclusive-or operations.
			while (FindMsbSet(value_Renamed) >= msbSetInPoly)
			{
				value_Renamed ^= poly << (FindMsbSet(value_Renamed) - msbSetInPoly);
			}
			// Now the "value" is the remainder (i.e. the BCH code)
			return value_Renamed;
		}
		
		// Make bit vector of type information. On success, store the result in "bits" and return true.
		// Encode error correction level and mask pattern. See 8.9 of
		// JISX0510:2004 (p.45) for details.
		public static void  MakeTypeInfoBits(ErrorCorrectionLevel ecLevel, int maskPattern, BitVector bits)
		{
			if (!QRCode.IsValidMaskPattern(maskPattern))
			{
				throw new WriterException("Invalid mask pattern");
			}
			int typeInfo = (ecLevel.Bits << 3) | maskPattern;
			bits.appendBits(typeInfo, 5);
			
			int bchCode = CalculateBchCode(typeInfo, TYPE_INFO_POLY);
			bits.appendBits(bchCode, 10);
			
			BitVector maskBits = new BitVector();
			maskBits.appendBits(TYPE_INFO_MASK_PATTERN, 15);
			bits.xor(maskBits);
			
			if (bits.size() != 15)
			{
				// Just in case.
				throw new WriterException("should not happen but we got: " + bits.size());
			}
		}
		
		// Make bit vector of version information. On success, store the result in "bits" and return true.
		// See 8.10 of JISX0510:2004 (p.45) for details.
		public static void  MakeVersionInfoBits(int version, BitVector bits)
		{
			bits.appendBits(version, 6);
			int bchCode = CalculateBchCode(version, VERSION_INFO_POLY);
			bits.appendBits(bchCode, 12);
			
			if (bits.size() != 18)
			{
				// Just in case.
				throw new WriterException("should not happen but we got: " + bits.size());
			}
		}
		
		// Check if "value" is empty.
		private static bool IsEmpty(int value_Renamed)
		{
			return value_Renamed == - 1;
		}
		
		// Check if "value" is valid.
		private static bool IsValidValue(int valueRenamed)
		{
			return (valueRenamed == - 1 || valueRenamed == 0 || valueRenamed == 1); // Dark (black).
		}
		
		private static void  EmbedTimingPatterns(ByteMatrix matrix)
		{
			// -8 is for skipping position detection patterns (size 7), and two horizontal/vertical
			// separation patterns (size 1). Thus, 8 = 7 + 1.
			for (int i = 8; i < matrix.Width - 8; ++i)
			{
				int bit = (i + 1) % 2;
				// Horizontal line.
				if (!IsValidValue(matrix.GetRenamed(i, 6)))
				{
					throw new WriterException();
				}
				if (IsEmpty(matrix.GetRenamed(i, 6)))
				{
					matrix.SetRenamed(i, 6, bit);
				}
				// Vertical line.
				if (!IsValidValue(matrix.GetRenamed(6, i)))
				{
					throw new WriterException();
				}
				if (IsEmpty(matrix.GetRenamed(6, i)))
				{
					matrix.SetRenamed(6, i, bit);
				}
			}
		}
		
		// Embed the lonely dark dot at left bottom corner. JISX0510:2004 (p.46)
		private static void  EmbedDarkDotAtLeftBottomCorner(ByteMatrix matrix)
		{
			if (matrix.GetRenamed(8, matrix.Height - 8) == 0)
			{
				throw new WriterException();
			}
			matrix.SetRenamed(8, matrix.Height - 8, 1);
		}
		
		private static void  EmbedHorizontalSeparationPattern(int xStart, int yStart, ByteMatrix matrix)
		{
			// We know the width and height.
			if (HORIZONTAL_SEPARATION_PATTERN[0].Length != 8 || HORIZONTAL_SEPARATION_PATTERN.Length != 1)
			{
				throw new WriterException("Bad horizontal separation pattern");
			}
			for (int x = 0; x < 8; ++x)
			{
				if (!IsEmpty(matrix.GetRenamed(xStart + x, yStart)))
				{
					throw new WriterException();
				}
				matrix.SetRenamed(xStart + x, yStart, HORIZONTAL_SEPARATION_PATTERN[0][x]);
			}
		}
		
		private static void  EmbedVerticalSeparationPattern(int xStart, int yStart, ByteMatrix matrix)
		{
			// We know the width and height.
			if (VERTICAL_SEPARATION_PATTERN[0].Length != 1 || VERTICAL_SEPARATION_PATTERN.Length != 7)
			{
				throw new WriterException("Bad vertical separation pattern");
			}
			for (int y = 0; y < 7; ++y)
			{
				if (!IsEmpty(matrix.GetRenamed(xStart, yStart + y)))
				{
					throw new WriterException();
				}
				matrix.SetRenamed(xStart, yStart + y, VERTICAL_SEPARATION_PATTERN[y][0]);
			}
		}
		
		// Note that we cannot unify the function with embedPositionDetectionPattern() despite they are
		// almost identical, since we cannot write a function that takes 2D arrays in different sizes in
		// C/C++. We should live with the fact.
		private static void  EmbedPositionAdjustmentPattern(int xStart, int yStart, ByteMatrix matrix)
		{
			// We know the width and height.
			if (POSITION_ADJUSTMENT_PATTERN[0].Length != 5 || POSITION_ADJUSTMENT_PATTERN.Length != 5)
			{
				throw new WriterException("Bad position adjustment");
			}
			for (int y = 0; y < 5; ++y)
			{
				for (int x = 0; x < 5; ++x)
				{
					if (!IsEmpty(matrix.GetRenamed(xStart + x, yStart + y)))
					{
						throw new WriterException();
					}
					matrix.SetRenamed(xStart + x, yStart + y, POSITION_ADJUSTMENT_PATTERN[y][x]);
				}
			}
		}
		
		private static void  EmbedPositionDetectionPattern(int xStart, int yStart, ByteMatrix matrix)
		{
			// We know the width and height.
			if (POSITION_DETECTION_PATTERN[0].Length != 7 || POSITION_DETECTION_PATTERN.Length != 7)
			{
				throw new WriterException("Bad position detection pattern");
			}
			for (int y = 0; y < 7; ++y)
			{
				for (int x = 0; x < 7; ++x)
				{
					if (!IsEmpty(matrix.GetRenamed(xStart + x, yStart + y)))
					{
						throw new WriterException();
					}
					matrix.SetRenamed(xStart + x, yStart + y, POSITION_DETECTION_PATTERN[y][x]);
				}
			}
		}
		
		// Embed position detection patterns and surrounding vertical/horizontal separators.
		private static void  EmbedPositionDetectionPatternsAndSeparators(ByteMatrix matrix)
		{
			// Embed three big squares at corners.
			int pdpWidth = POSITION_DETECTION_PATTERN[0].Length;
			// Left top corner.
			EmbedPositionDetectionPattern(0, 0, matrix);
			// Right top corner.
			EmbedPositionDetectionPattern(matrix.Width - pdpWidth, 0, matrix);
			// Left bottom corner.
			EmbedPositionDetectionPattern(0, matrix.Width - pdpWidth, matrix);
			
			// Embed horizontal separation patterns around the squares.
			int hspWidth = HORIZONTAL_SEPARATION_PATTERN[0].Length;
			// Left top corner.
			EmbedHorizontalSeparationPattern(0, hspWidth - 1, matrix);
			// Right top corner.
			EmbedHorizontalSeparationPattern(matrix.Width - hspWidth, hspWidth - 1, matrix);
			// Left bottom corner.
			EmbedHorizontalSeparationPattern(0, matrix.Width - hspWidth, matrix);
			
			// Embed vertical separation patterns around the squares.
			int vspSize = VERTICAL_SEPARATION_PATTERN.Length;
			// Left top corner.
			EmbedVerticalSeparationPattern(vspSize, 0, matrix);
			// Right top corner.
			EmbedVerticalSeparationPattern(matrix.Height - vspSize - 1, 0, matrix);
			// Left bottom corner.
			EmbedVerticalSeparationPattern(vspSize, matrix.Height - vspSize, matrix);
		}
		
		// Embed position adjustment patterns if need be.
		private static void  MaybeEmbedPositionAdjustmentPatterns(int version, ByteMatrix matrix)
		{
			if (version < 2)
			{
				// The patterns appear if version >= 2
				return ;
			}
			int index = version - 1;
			int[] coordinates = POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index];
			int numCoordinates = POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index].Length;
			for (int i = 0; i < numCoordinates; ++i)
			{
				for (int j = 0; j < numCoordinates; ++j)
				{
					int y = coordinates[i];
					int x = coordinates[j];
					if (x == - 1 || y == - 1)
					{
						continue;
					}
					// If the cell is unset, we embed the position adjustment pattern here.
					if (IsEmpty(matrix.GetRenamed(x, y)))
					{
						// -2 is necessary since the x/y coordinates point to the center of the pattern, not the
						// left top corner.
						EmbedPositionAdjustmentPattern(x - 2, y - 2, matrix);
					}
				}
			}
		}
	}
}